Reference number of working document:
ISO/TC 23/SC 19/WG3/N 221Date:
1999-08-05 ISO/WD 14223/1 ISO/TC 23/SC 19/WG 3 W.J.EradusRadio frequency identification of Animals, advanced transponders – Air interface
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Contents
Radio frequency identification of Animals, advanced transponders – Air interface
*1 Scope
*2 Conformance
*3 Normative references
*4 Terms and definitions
*5 Symbols (and abbreviated terms)
*6 General requirements
*7 FDX-B20 transponder: down-link
*7.1 Down-link, description
*7.2 Mode switching, protocol
*7.3 Mode switching, modulation
*7.4 Mode switching, modulation details
*7.5 Down-link communication, protocol
*7.6 Down-link communication, modulation
*7.7 Down-link communication, modulation details
*8 FDX-B100 transponder: down-link
*8.1 Down-link description
*8.2 Mode switching, protocol
*8.3 Mode switching, modulation
*8.4 Down-link communication, modulation details
*8.5 Down-link communication, protocol
*8.6 Down-link communication, modulation
*8.7 Down-link communication, modulation details
*9 HDX-ADV transponder: down-link
*9.1 Down-link description
*9.2 Mode-switching, protocol
*9.3 Mode switching, modulation
*9.4 Mode switching, modulation details
*9.5 Down-link communication, timing
*9.6 Down-link communication, Bit encoding
*9.7 Down-link communication, modulation details
*Annex A, summary of down-link interfaces………………………………………….……………….……….18
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3.
Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this part of ISO 14223/1 may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
International Standard
ISO 14223/1 was prepared by Technical Committee ISO/TC 23, Subcommittee SC 19, Working group WG3.ISO 14223
consists of the following parts, under the general title:¾
Part 1:Radio Frequency Identification of Animals, Advanced transponders ¾ air interface¾
Part 2: Radio Frequency Identification of Animals, Advanced transponders ¾ code- and command structure¾
Part 3: Radio Frequency Identification of Animals, Advanced transponders ¾ applications
This International Standard specifies the structure of the radio frequency (RF) code for advanced transponders for animals. The technical concept of advanced transponders for animal identification described is based upon the principle of radio frequency identification (RFID) and is an extension of the standards ISO 11784 and ISO 11785. Apart from the transmission of the (unique) identification code of animals, application of advanced technologies facilitates the storage and retrieval of additional information (integrated database), the implementation of authentication methods and reading of the data of integrated sensors, etc. This standard consists of three parts as described in the foreword.
Attention is drawn to the possibility that some of the elements of this International Standard may be the subject of patent rights other than those identified above. ISO shall not be held responsible for identifying any or all such patent rights.
Radio frequency identification of Animals, advanced transponders – Air interface
This part of the standard describes the air interface between transceiver and advanced transponder under condition of a full downward compatibility of ISO 11784 and ISO 11785. Thus this standard must be regarded as an extension of ISO 11785 and must be used in conjunction with it.
Transponders are in conformance with this part of the International Standard provided they meet clause (7 OR 8 OR 9) AND 6 of this International Standard. Transceivers are in conformance with this part of the International Standard provided they meet the requirements of clause 6 AND 7 AND 8 AND 9 of this International Standard.
The following normative documents contain provisions which, through reference in this text, constitute provisions of this part of ISO 14223. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this part of ISO 14223 are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards.
ISO 11784; 1996, Radio Frequency Identification (RFID) of Animals – Code structure
ISO11785; 1996, Radio-frequency identification of animals-Technical concept
For the purposes of this part of ISO 14223, the following terms and definitions apply.
Advanced transponder: Transponder, downward compatible according ISO 11784 and ISO 11785 with facilities for storage and retrieving additional data, implemented authentication methods, integrated sensors etc.
Advanced mode: Working principle of the advanced transponder after the switching command
Basic Time Unit: Time of one period of interrogation frequency.
Binary Pulse length encoding: Method of encoding in which data bit 0 is represented by a modulation index of 0 to 10% modulation depth during 7 btu’s, followed by a modulation index of 100% during 20 btu’s and in which data bit 1 is represented by a modulation index of 0 to 10% modulation depth during 7 btu’s, followed by a modulation index of 100% during 30 btu’s
Bit rate: The number of bits transmitted per second.
Differential bi-phase encoding: Method of encoding in which data bit 0 is represented by a mid-bit transition; data bit 1 is represented by no transition; and there is always a transition in between two bits.
Down-link: The transmission of data or commands from transceiver to transponder
Encoding: The one to one relationship between basic information elements and modulation patterns.
Error detection code: Bits that contain information which can be used to detect errors.
FDX-B20: Air interface for FDX-B advanced transponders with low modulation depth.
FDX-B100: Air interface for FDX-B advanced transponders with high modulation depth.
Frequency shift keying: Binary information is superimposed onto a carrier electromagnetic field by shifting between discrete frequencies of the field.
Full duplex: Method of information exchange in which the information is communicated while the transceiver transmits the interrogation field.
Half duplex: Method of information exchange in which the information is communicated after the transceiver has stopped transmitting the interrogation field.
HDX-ADV: Air Interface for HDX advanced transponders.
Header: Bits transmitted before the useful information, uniquely identifying the start of a page, which may also be used for synchronisation of the transponder and the transceiver.
Interrogation field:
Interrogation frequency: Frequency of the interrogation field.
Interrogation period: The time duration of the interrrogation signal.
Instruction or command: Bit pattern downloaded to the advanced transponder to modify its status
ISO 11785 frame The total identification message (header, identification code, error detection code and trailer), possibly repeatedly transmitted by the transponder upon activation.
Mobile transceiver: Usually hand-held transceiver, not synchronised by wire to other transceivers.
Modulation: Method of superimposing information onto an interrogation field by means of varying a specific parameter of the field.
Non-return to zero encoding: Method of encoding in which data bit 1 is a high signal; and data bit 0 is a low signal.
Phase shift keying: Binary information is superimposed onto a carrier magnetic field by introducing discrete phase shifts of the field.
Stationary transceiver: Non-mobile transceiver that may be connected to a host computer, may also be connected to other transceivers to synchronise activation periods and pauses.
Switch code: Bit pattern used to switch and advanced transponder to the advanced mode.
Switch off time: Time interval wherein the interrogation field is switched off.
Switch window: Time interval wherein a FDX-B100 transponder can be switched into the advanced mode.
Trailer: Bits transmitted after the error detection code. The content of the trailer is dependent upon the value of the flag for an additional data block which is specified in ISO 11784.
Transceiver: Device used to communicate with a transponder.
Transponder: Electronic device which is activated by a transceiver and communicates with it.
Type code A bit pattern which specifies the used down-link mode.
Up-link: The transmission of data from transponder to transceiver
5 Symbols (and abbreviated terms)
ASK:
Amplitude Shift keyingCRC: Cyclic Redundancy Check
FDX: Full Duplex
HDX: Half Duplex
LSB: Least significant bit
MSB: Most significant bit
RFID: Radio Frequency Identification
PWM Pulse Width Modulation
btu Basic Time Unit (1 period of interrogation frequency).
6 General requirements
The advanced ISO transponders described in this document shall be fully backwards compatible with ISO-11784 and ISO-11785. After the advanced transponder is placed in the interrogation field, it shall perform like transponders according to ISO-11785. The advanced transponder shall send type information in the reserved bit field to the transceiver. To bring the advanced transponder into the advanced mode, the transceiver shall modulate the interrogation field. The details of this procedure for every protocol are described in the relevant chapters of this standard. When the advanced transponder has detected this modulation of the interrogation field, it shall switch to the advanced mode. In this advanced mode, the advanced transponder shall only respond when instructed by the transceiver. The transponder shall switch back to the ISO 11785 mode when:
The off-time shall be extended up to 20 ms, depending on the presence of a HDX transponder.
All data telegrams from transceiver to transponder and vice versa shall be in accordance with ISO 11785 and ISO 14223/2. The identification code, all data telegrams from transceiver to transponder and vice versa and the CRC error detection bits (if applicable) shall be transmitted starting with the LSB and ending with the MSB.
Bit 16 of the 11785-frame (additional data flag) shall be set to "1", indicating that the transponder contains additional data. The transmission parameters of the up-link in advanced mode are the same as defined in ISO 11785.
See figure 1. After receiving and decoding the ISO 11785 frame (T), the transceiver shall detect the presence of an advanced transponder in the interrogation field.
In order to bring the FDX-B20 transponder into the advanced mode, the transceiver modulates the interrogation field the while the ISO 11785 header is transmitted (B).
After receiving the correct mode switching pattern from the transceiver, the FDX-B20 transponder shall stop transmitting its ISO 11785 transponder code (T) and switch to the advanced mode and shall wait for instructions from the transceiver (C).
The down-link communication takes place in period C and D. The example in figure 1 shows two data blocks (X1 and X2) being selected by the transceiver, which then are transmitted by the transponder.
The FDX-B20 transponder shall return to the ISO 11785 FDX-B mode after switching off of the interrogation field (E) for at least 3 ms, identical to ISO 11785.
Cycle A: the transceiver reads the ISO 11785 frame. The bits in the reserved field of the ISO 11785 code indicate to the transceiver that an advanced FDX-B20 transponder is in the interrogation field.
Cycle B: mode switching: the transceiver modulates the interrogation field while the transponder transmits the ISO 11785 header.
Cycle C: down-link communication: the transceiver sends commands to the transponder by modulating the interrogation field.
Cycle D: Read/Write operations in advanced mode
Cycle E: After all operations are finished, or transponder left the antenna field, the transceiver switches off the field for at least 3 ms.
The advanced transponder shall switch to the advanced mode after receiving the correct mode switching pattern from the transceiver. Refer to table 1 for details.
|
Amplitude Modulation (ASK), 10-25% |
|
Manchester: ‘0’ = rising edge in the middle of a bit ‘1’ = falling edge in the middle of a bit |
|
2097 bits/sec. Least Significant Bit (LSB) first |
|
Specific 4 bit pattern (1011, LSB first) while the ISO 11785 header modulation. Carrier modulation synchronous with transponder bit transitions. |
table 1 — Mode switching parameters for a FDX-B20 transponder
Mode switching is according to a specific 4 bit pattern (1011), executed when the advanced FDX-B20 transponder transmits the ISO 11785 header. Interrogation field modulation is synchronous with transponder bit transitions.
Figure 2 — Mode switching FDX-B20: modulation and timing.
Figure 3 — Interrogation field modulation details
|
(a-b)/(a+b) (%) |
t1 (btu) |
t2 (btu) |
t3 (msec.) |
t4 (msec.) |
y |
hf, hr (max.) |
|
|
Min. |
10 |
32 (00 or 11) or 64 (01 or 10) |
32 (00 or 11) or 64 (01 or 10) |
0 |
0 |
0.05 x (a-b) |
0.01 x (a-b) |
|
Max. |
25 |
0.2 |
0.2 |
Compared to the mode switching protocol, all parameters in the down-link communication protocol are equal, except for the bit rate of the interrogation field modulation. In the case of down-link communication the bit rate is equal to the ISO 11785 bit rate.
|
Amplitude Modulation (ASK), 10-25% |
|
Manchester: ‘0’ = rising edge in the middle of a bit ‘1’ = falling edge in the middle of a bit |
|
4194 bits/sec (ISO 11785 FDX-B). Least Significant Bit (LSB) first. |
Table 3 — Down-link modulation parameters for a FDX-B20 transponder
The transponder shall not modulate the interrogation field during transceiver down-link modulation. In the example of figure 4, the transceiver transmits the instruction 01001000 (LSB first).
Figure 4 — Down-link modulation for a FDX-B20 transponder
Figure 5 — Down-link modulation details of data transmission from transceiver to transponder
|
(a-b)/(a+b) (%) |
t1 (btu) |
t2 (btu) |
t3 (msec.) |
t4 (msec.) |
y |
hf, hr (max.) |
|
|
Min. |
10 |
16 (00 or 11) or 32 (01 or 10) |
16 (00 or 11) or 32 (01 or 10) |
0 |
0 |
0.05 x (a-b) |
0.01 x (a-b) |
|
Max. |
25 |
0.2 |
0.2 |
FDX-B100 transponder: down-link Down-link description
After receiving and decoding the ISO11785 frame of the transponder code, the transceiver shall detect the presence of an advanced transponder in the interrogation field. To bring the FDX-B100 transponder into the advanced mode, the transceiver’s interrogation field shall be switched off. After this off- period, the interrogation field shall be switched on again, and a 5-bit SWITCH command shall be sent to the transponder within a specified listening window. The transponder shall switch itself into the advanced mode upon reception of the SWITCH command. In this advanced mode, the FDX-B100 transponder shall only respond when instructed by the transceiver (transceiver driven protocol).
The advanced transponder switches back to the ISO 11785 mode after the interrogation field has been switched off for at least 3 ms. The steps necessary to bring the FDX-B100 transponder into the advanced mode are shown in figure 6. The down-link communication takes place in period C and D. The example in figure 6 shows two data blocks (X1 and X2) being selected by the transceiver, which then are transmitted by the transponder.
Figure 6 — Example of an interrogation sequence of a FDX-B100 transponder
Cycle A: the transceiver reads the ISO 11785 frame. With the bits in the reserved field the transceiver detects, that an advanced FDX-B100 transponder is in the interrogation field.
Cycle B: the transceiver switches off the interrogation field for at least 3 ms in order to reset the transponder.
Cycle C: the transceiver sends a SWITCH command to the transponder in order to bring it into the advanced mode. The SWITCH command must be issued within a switch window after reset.
Cycle D: Read/Write operations in advanced mode
Cycle E: After all operations are finished, or transponder left the antenna field, the transceiver switches off the field for at least 3 ms. in order to poll for new incoming transponders (compatible with ISO11785).
The FDX-B100 transponder shall switch to the advanced mode after receiving the correct switch command from the transceiver during the specified switch window after power-up. Refer to table 3 for details.
|
Amplitude Modulation (ASK), 90 - 100% |
|
Binary Pulse Length |
|
6000 bits/sec. typical, Least Significant Bit (LSB) first |
|
Specific 5 bit switch command, transmitted after a interruption of the interrogation field of at least 3ms. |
|
Transponder settling time: 312.5 btu |
|
11000 |
|
minimum 36 btu |
table 5 — Air interface parameters for FDX-B100 mode switching protocol
Figure 7 — Example of down-link modulation pattern for a FDX-B100 transponder.
|
(a-b)/(a+b) (%) |
t1 (btu) |
t2 |
t3 |
t4 |
y |
hf, hr (max.) |
|
|
Min. |
90 |
4 |
‘0’= 18 btu – t1 or ‘1’ = 26 btu – t1 |
not applicable |
not applicable |
t.b.d. |
t.b.d. |
|
Max. |
100 |
10 |
‘0’= 22 btu – t1 or ‘1’ = 32 btu – t1 |
0.2 |
0.2 |
t.b.d. |
t.b.d. |
|
Amplitude Modulation (ASK), 90-100% |
|
Binary Pulse Length |
|
6000 bits/sec. typical, Least Significant Bit (LSB) first |
Table 7 — Air interface parameters for FDX-B100 down-link communication
Down-link communication, modulationHDX-ADV transponder: down-link Down-link description
Since the HDX-ADV transponder uses half duplex communication, it can be switched into the advanced mode at every interrogation cycle. In order to bring the transponder into the advanced mode, the second part of the interrogation field burst shall be modulated with a command code and eventually data to be written. After receiving the correct command code, the transponder shall respond with the data according this command in the subsequent off time of the interrogation field (READ interval). The down-link communication takes place in period C and D. The example in figure 9 shows two data blocks (X1 and X2) being selected by the transceiver, which then are transmitted by the transponder.
Figure 9 — RF interface for ISO compatible advanced HDX transponders.
Cycle A: the transceiver switches on the interrogator field to charge the ISO 11785 HDX compliant transponder or the advanced transponder for a time of 50-100ms depending of the presence of a FDX-B transponder.
Cycle B: the transceiver switches off the interrogator field for 20ms in order to read the ISO HDX compliant transponder or the first frame of the advanced transponder.
Cycle C: the transceiver modulates the interrogator field according to the encoded down-link data to transmit data and commands to the ISO HDX-ADV compliant transponder.
The HDX-ADV transponder shall switch to the advanced mode upon reception of a valid command after the charge phase. The commands have simultaneously the function of switch command and instruction code for the transponder how to respond. At every new interrogation cycle, the transponder starts up again and will be in ISO11785 mode if no further command is transmitted by the transceiver.
Not applicable
Not applicable
|
Amplitude Modulation (ASK), 90-100% |
|
Pulse Width Modulation (PWM) |
|
500 bits/sec |
Table 8 —Air interface parameters for HDX-ADV down-link
The write function is used to transfer commands, block addresses and data to the transponder in order to activate certain functions (Down-link).The down-link communication procedure shall start immediately after the charge phase and is achieved by modulating the RF transmitter. The down-link communication procedure is different for writing data to the transponder and for programming data into the transponder’s memory. The writing procedure’s timings are according to figure10.
Programming shall be executed after the write function. During programming, the transceiver’s interrogation field is continuously ON for at least 15ms.
The Down-link bits shall be coded using Pulse Width Modulation (PWM). The duration of the transmitter deactivation (TX-OFF) shall define whether it is a Low bit or a High bit. During a High bit the transmitter shall be deactivated for a toffH and shall be activated afterwards for a tonH time frame. During a Low bit the transmitter shall be deactivated for a toffL and shall be activated afterwards for a tonL time frame.
Figure 10 — Down-link bit encoding (digital transmit energy control signal)
|
PARAMETER |
CONDITION |
MIN. |
NOM. |
MAX. |
UNIT |
|
|
Typical Bit duration |
tbit |
1.95 |
2 |
2.1 |
ms |
|
Table 9 — Down-link bit encoding timings
For the down-link data/command transmission a Pulse Width Modulation (PWM) is used with a modulation index of about 90 to 100 %. The signal conditions at the transponder resonance circuit independent of the system parameters are defined in Figure 11.
Figure 11 — Down-link modulation at the transponder antenna.
|
Low bit |
High bit |
|||
|
Min. |
Max. |
Min. |
Max. |
|
|
t1 (msec.) |
0 |
0.2 |
0 |
0.2 |
|
toff (msec.) |
0.1 |
0.69 |
0.74 |
1.8 |
|
toff (msec.) |
1.95 |
2.1 |
1.95 |
2.1 |
Note: From the transponder point of view a toff(H/L) signal length threshold is defined to distinguish between High and Low bit. tthrs=96/f» 715usec (where f represents the transponder resonance frequency). Low bit: toffL< tthrs. High bit: toffH³ tthrs
Annex A
|
Parameter |
FDX-B20 |
FDX-B100 |
HDX |
|
Down-link frequency |
134,2 kHz |
134,2 kHz |
134,2 kHz |
|
Modulation (depth) |
ASK (10 – 25%) |
ASK (90 - 100%) |
ASK (90 - 100%) |
|
Encoding |
Manchester |
Binary Pulse Length |
PWM |
|
Bit rate |
4194 bits/s. |
Typ. 6000 bits/s |
500 bits/s |
|
Switch code modulation |
ASK (10 –25%) |
ASK (90 - 100%) |
Not applicable |
|
Switch code encoding |
Manchester |
Binary Pulse Length |
Not applicable |
|
Switch code Bit rate |
2097 bit/s, LSB first |
Typ. 6000 bits/s |
Not applicable |
Summary of the down-link air interfaces of FDX and HDX systems
Note In most countries the use of transceivers as described in this International Standard is subject to regulations. Type approval from the national regulatory agencies may be required before they can be operated or traded in these countries.
